The short list of devices is primarily due to something weird b-mobile does with their data-only SIMs; they remove the voice component entirely, which a lot of phones don't expect, thus you might get odd errors or don't see any signal when there should be if the phone can't handle this. You don't see this in data SIMs from other countries because the voice component is still there, even if it redirects everything to a "you can't make calls from this device" prompt or something similar.